November 17, 2023

How Long Does Fentanyl Stay in your System

If you've found yourself addicted to fentanyl, you're probably wondering how long fentanyl stays in your system. Here we give you answers along with resources to guide you towards recovery.

Table of Contents

Table of Contents

Contributors & Editors

Susana Spiegel

Recovery Writer and Advocate

Last Update on November 17, 2023

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How long does fentanyl stay in your system? The answer to this question is important to know for individuals consuming fentanyl, as well as medical and addiction treatment professionals. 

Over the last ten or more years, fentanyl has become a pervasive and leading part of the illicit drug market in the United States and around the world. 

This powerful manufactured opioid, often laced unknowingly in other drugs, has led to a surge in overdoses and fatalities. Understanding how long fentanyl is detected in the body is an important part of the overall knowledge of the this drug. 

How Long Fentanyl Stays in The System

Understanding how long fentanyl remains in the body is important for both medical professionals and individuals potentially taking it.

The detection period for fentanyl in the body fluctuates based on various factors.

While it may leave the bloodstream relatively quickly, it can linger in other parts of the body for an extended period of time.


Factors that Influence Fentanyl Detection Times in Your System

Fentanyl detection times in body fluids vary depending on the method of administration and the type of fluid tested. Here are some key findings on the factors that come into play: 


Factor Impact on Fentanyl in System
Metabolism Faster metabolism leads to quicker processing and elimination.
Frequency and Amount of Use Regular/heavy use prolongs detection, while infrequent/light use shortens it.
Body Mass Higher body fat can retain fentanyl longer.
Age Older adults may retain fentanyl longer due to slower metabolism.
Kidney and Liver Function Impaired function can slow down metabolism and excretion.
Hydration and Diet Nutrition and Hydration affect how quickly the body processes fentanyl.
Genetic Factors Genetic variations influence metabolism rates.
Overall Health General health and medical conditions impact drug processing and elimination.

This knowledge is not only crucial for health and safety reasons but also for understanding the importance of interventions such as an addiction treatment setting where fentanyl use is a concern. 

Detection of Fentanyl in Drug Tests

Fentanyl, due to its potent nature and high risk of addiction and overdose, is a substance that is frequently tested for in various drug screening methods. The type of drug test used can significantly impact the detection window and the reliability of identifying fentanyl use.

Fentanyl Detection in Blood Tests

Blood tests offer a quick way to detect the presence of Fentanyl, but their detection window is quite short, typically up to 24 hours after use.

This method is most effective in acute medical settings or soon after suspected use.

Fentanyl Detection in Urine Tests

Urine testing is the most common method for detecting Fentanyl and its metabolites.

It can identify the drug for up to seventy-two hours post-use, making it useful for medical and legal screenings.


Fentanyl Detection in Hair Follicle Test 

Hair tests provide the longest detection window.

Fentanyl can be traced in hair for up to three months after use, offering a detailed view of a person’s drug history.

This method is less common due to its cost and time to obtain results.


Fentanyl Detection in Saliva Tests

Saliva tests are less invasive and can detect Fentanyl soon after use, generally within minutes to an hour. 

However, their detection window is relatively short, similar to blood tests. 

Each choice of test tends to depend on each situation and the urgency of the context of the situation.

For instance, in emergency medical scenarios, blood tests may be preferred, while urine tests are commonly used in rehabilitation settings, like rehab for fentanyl addiction. 

Each testing method has advantages and limitations, making it important to select the right one based on the specific need and timeframe for fentanyl use.


Visual Table of Fentanyl Detection Windows  


Body System Fentanyl Detection Period
Blood Test Up to 24 hours
Urine Test Up to 72 hours
Hair Follicle Test Up to 90 days
Saliva Test 24 hours to 
Sweat up to 22 days1 

How Fentanyl Moves Through the Body

Researchers looked at how fentanyl moved in the bodies of 7 healthy men who were given a specific dose. They checked the men’s blood and urine for fentanyl and other related substances.

They found that the level of fentanyl in the blood dropped quickly, and within an hour, almost all of it was gone from the blood. However, getting rid of fentanyl completely from the body took much longer. This is because fentanyl moves from different parts of the body back into the blood, where it is then broken down and eliminated, mostly in urine and feces.2

Even though most of the fentanyl was gone from the blood quickly, it took about 3 days to get most of it out of the body. Also, the amount of fentanyl in the blood went up and down during this time.

Detecting Fentanyl After Death

Fentanyl can still be found in a person’s body for up to two weeks3 after the person fatally overdoses. 

This is because fentanyl and the substances it turns into in the body can stay in different parts of the body, like blood and organs, for a long time.

Scientists use special equipment to find even tiny amounts of fentanyl in the body after someone has passed away. This is important to help figure out what caused the death and to help with efforts to deal with the problem of people using too much fentanyl.

Treatment and Resources

Treatment for Fentanyl addiction typically involves a combination of medical and therapeutic interventions, along with access to various resources.



This initial phase is intimidating but necessary, cleansing the body of opioids under medical supervision to manage withdrawal symptoms safely.


Rehabilitation Programs

This can vary, whether it be inpatient or residential treatment for fentanyl or outpatient, as well as therapy, counseling, and support to address the psychological aspects of addiction.


Medically Assisted Fentanyl Detox

Medications like buprenorphine are used by physicians during fentanyl detox to manage withdrawal symptoms, combined with counseling and behavioral therapies.


Support Groups

Groups like Narcotics Anonymous provide peer support and a sense of community for those in recovery.

Fentanyl is a really dangerous addiction and shouldn’t be taken lightly.

Cornerstone Healing Center is a fentanyl treatment program that can help you begin the process of recovery from fentanyl addiction. 

If you or someone you care about is facing fentanyl addiction and/or mental health challenges, we encourage you to contact us. We also specialize in treating co-occurring mental health and substance use disorders. 

Get Help for Fentanyl Abuse Today

Fentanyl, a highly potent drug, poses significant risks due to its powerful effects and potential for addiction.

The risks extend from short-term health impacts to severe long-term consequences, including a high potential for fatal overdoses.

Equally important is knowing where to seek help.

Cornerstone Healing Center offers specialized rehab for Fentanyl abuse, providing a supportive environment for overcoming addiction.

Taking the first step towards recovery is crucial.

If you or someone you know is struggling with Fentanyl abuse, don’t hesitate to seek help.

Our treatment facility is grounded in evidence-based practices and specializes in dual diagnosis, promoting long-term recovery by addressing underlying issues.

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Author & Reviewers

susana spiegel recovery writer and SEO expert

Susana is a recovery writer and advocate with over 8 years in addiction recovery. She is passionate about sharing accurate and helpful information about mental health, addiction, and recovery. She holds a Bachelor’s in Christian Studies from Grand Canyon University and has over 7 years of working in the addiction field. 

lionel estrada lisac clinical director

Lionel is the Clinical Director of Cornerstone’s Scottsdale treatment facilities. He has had over 4 years at Cornerstone. He is personally in recovery and passionate about helping others overcome substance abuse and mental health challenges; he is trained as an EMDR, adopting a trauma-informed approach to treat the underlying issues.

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